Reduced Part Count Research Articles

A Novel Multigain Switched-Capacitor-Based Topology with Reduced Part Count

A Novel Multigain Switched-Capacitor-Based Topology with Reduced Part Count

Switched-Capacitor-Based Multi-Source Multilevel Inverter With Reduced Part Count

This paper proposes a switched-capacitor (SC) based multi-source multilevel inverter (MSMLI) for high-frequency AC power distribution systems. The proposed topology is a potential alternative in applications involving asymmetric dc voltage sources (in the case of renewable source-based AC microgrids). Using the available dc sources as an aggregated input eliminates the need for paralleling of inverters. In addition, the proposed topology offers a common ground among the multiple input sources and, thus, has a more straight forward design and avoids stacking voltage sources. By employing nine switches, two diodes, and two SCs, an 11-level voltage waveform is synthesized. The SC voltages are self-balanced owing to their series-parallel charging technique. A simple selective harmonic elimination technique is used to obtain the desired output voltage level and simultaneously eliminate the lower-order harmonics. A detailed comparison of the proposed MSMLI is carried out, and the test results obtained from a laboratory prototype are presented to validate the feasibility and highlight the benefits of the proposed topology.

3D Printing a Low‐Cost Miniature Accommodating Optical Microscope (Adv. Mater. 20/2023)

3D Printing In article number 2208365, Rihan Hai, Cheng Sun, and co-workers report a method for 3D printing the key optical and optomechanical components of a miniature accommodating optical microscope in 50 min for less than $4. Synergizing the built-in voice-coil-motor and compliant optomechanics facilitates focus stacking functionality for extending imaging depth. 3D printing enables digitized component manufacturing, part-count reduction, and passive alignment for the ease of system miniaturization and assembly, allowing rapid customizability toward task-specific needs.

A Single Source Self-Balanced Boost MLI with Reduced Part Count for EV Applications

As the use of inductor-based topologies demands a large amount of space, capacitor-based topologies have garnered attention. Electric Vehicles (EVs) are usually equipped with two-level inverters, which require separate control strategies for each level and synchronizing the strategies increases the complexity of operation and makes them unreliable. Therefore, a single-stage converter with boost and conversion abilities with better power quality at optimal component count and efficiency is needed. A novel capacitor-based boost multilevel inverter (CB-MLI) topology is proposed in this paper as it is found suitable for EV and HEV applications. It is capable of generating an eleven-level waveform with only eleven switches, three capacitors, and a single isolated source. The self-balancing property of the capacitors makes the topology one of a kind. A constant carrier PWM-based control strategy is utilized to switch the IGBTs. Testing results from hardware setup confirm the proposed capacitor-based CB-MLI topology operating modes and potentiality. Lastly, by highlighting the proposed and existing MLI circuits, the benefits of the recommended configuration are outlined by component count and total cost. Additionally, it is a simplified design that needs fewer footprint areas and space.

Additive manufacturing of titanium alloys – Enabling re-manufacturing of aerospace and biomedical components

This paper describes the state of the art of additive manufacturing of Titanium alloys especially in the high-value-materials industries such as aerospace and biomedical. In such industries, the high value components like aerospace gas engine turbine blades or the coronary angioplasty stents in biomedical industry call especially for the re-manufacturing vision that is only recently enabled by additive manufacturing methodologies. This paper starts by describing the two most common additive manufacturing (AM) methods as characterized by their input material forms: powder and wire. Using examples, it then provides an assessment of the status of these methods as regards to their maturity as production ready processes. Following this, the principal issues that must be addressed before AM can achieve this status are outlined. Perhaps the most critical one among these is development of a rapid qualification method for AM produced components. In this regard, the current method for qualifying different classes of components is outlined. Some suggestions for reducing the time required for qualification are made. Significant benefits of AM are described including part count reduction and the use of design synthesis to achieve significant component weight reduction. Two low risk examples of this are described herein. The Direct Energy Deposition (DED) model is highlighted especially in its role to enable the Re-Manufacturing vision for high-value structural components such as in aerospace and biomedical industries. This paper concludes that there are numerous opportunities for incorporation of components made by AM once some of the issues described are effectively addressed.

Optimizing Luminous Transmittance of a Three-Dimensional-Printed Fixed Bed Photobioreactor.

The development of innovative production processes and the optimization of photobioreactors play an important role in generating industrial competitive production technologies for phototrophic biofilms. With emerse photobioreactors a technology was introduced that allowed efficient surface attached cultivation of terrestrial cyanobacteria. However, the productivity of emerse photobioreactors depends on the available cultivation surface. By the implementation of biocarriers to the bioreactor volume, the cultivation surface can be increased which potentially improves productivity and thus the production of valuable compounds. To investigate the surface attached cultivation on biocarriers new photobioreactors need to be developed. Additive manufacturing (AM) offers new opportunities for the design of photobioreactors but producing the needed transparent parts can be challenging using AM techniques. In this study an emerse fixed bed photobioreactor was designed for the use of biocarriers and manufactured using different AM processes. To validate the suitability of the photobioreactor for phototrophic cultivation, the optical properties of three-dimensional (3D)-printed transparent parts and postprocessing techniques to improve luminous transmittance of the components were investigated. We found that stereolithography 3D printing can produce parts with a high luminous transmittance of over 85% and that optimal postprocessing by sanding and clear coating improved the clarity and transmittance to more than 90%. Using the design freedom of AM resulted in a bioreactor with reduced part count and improved handling. In summary, we found that modern 3D-printing technologies and materials are suitable for the manufacturing of functional photobioreactor prototypes.

Modular speaker design enabled by multi-material additive manufacturing

One of the most promising features of additive manufacturing is ability to reduce part count and assembly by printing complex shapes. This feature is further highlighted by utilizing multi-material printing in which stiff and compliant materials can be deposited by the same system. Air-acoustic speakers are traditionally comprised of several assembled components with different material properties including a stiff enclosure, stiff diaphragm, and compliant suspension. In this presentation, we will describe a modular acoustic speaker design. The design consists of fully printed structural components (which are threaded together, and assembled with a voice coil and magnet). The basic design as well as printing process will be described and acoustic measurements reported. A range of printed designs, which can be interchanged among each-other will be presented, and future design ideas which take advantage of the printing process explored.

Simplified configuration with reduced part count and improved total harmonic distortion for DC–AC conversion

The quality of power generation from various energy sources is essential for industrial and household applications. To achieve the quality of power by minimizing the total harmonic distortion (THD) through multi-level inverters (MLIs) is an attractive solution. MLIs have tremendous performance against %THD and electromagnetic interference (EMI) issues compared with the classical two-level inverters. However, MLIs have more device count and intricacy of the circuitry for further reducing the THD, which increases the complexity and cost of the converter. In the paper, a new approach is suggested for reducing the THD through the proposed inverter with a comparatively lower quantity of power electronic components and less control complexity. The proposed inverter is tested in the simulation environment and on an experimental test using low power (150 W) prototype circuit.

Comparative study of a bidirectional multi-phase multiinput converter for electric vehicles

Multiinput converters allow to create hybrid energy systems in electric vehicles with a reduced part count. In addition, interleaved structures help to build efficient converters with several possible benefits, such as low current ripple and high power density. This paper proposes utilizing a multiphase multiinput converter (MPMIC), which concentrates the aforementioned advantages and presents a comprehensive comparison with its single-phase version, called single phase multiinput converter (SPMIC). After analysing their steady-state characteristics, SPMIC and MPMIC are designed considering same conditions. Then, two laboratory prototypes rated at 2.5kW output power are implemented to validate the analysis. Finally, these prototypes are compared in terms of voltage-gain, input current ripple, efficiency, complexity, cost, and power density. The results show that MPMIC surpasses SPMIC in efficiency and in input current ripple at the expense of increments in the complexity and cost. Besides, MPMIC results in comparatively high voltage gain in low power region thanks to the discontinuous current mode operation. On the other hand, it is explored that SPMIC can reach higher power density in the event of effective cooling.

Modified W-type configuration for a single-phase reduced parts count 81-level inverter.

The technology of modern power systems is revolutionizing as renewable energy sources are being integrated with electric power grids. In the form of inverters, power electronic converters are becoming an integral part of power systems due to their massive demand for grid integration of photovoltaic (PV) systems. Existing multilevel inverter topologies either require an output filter to get a sinusoidal voltage or generate a higher number of output voltage levels at the expense of many hardware resources. This paper presents a new single-phase 81-level inverter configuration with the name given as 'Modified W-Type Multilevel Inverter'. The proposed inverter configuration uses only eighteen power switches and four DC voltage sources to generate an 81-level output voltage approaching a sinusoidal waveform without an output filter. The general design equations are developed to calculate the number of switches, the number of voltage levels, and the number of DC sources for the proposed configuration. Loss and efficiency analysis is carried out that verifies a good practical efficiency of the proposed inverter configuration during the dynamic operation. A comparative analysis with the existing MLI topologies is also carried out that validates the effectiveness and novelty in reducing parts count and higher number of voltage levels. The proposed topology offers 1.04% total harmonic distortion of the output voltage which is within the benchmarks specified for grid integration without any filter requirements. The proposed inverter configuration is simulated in MATLAB/Simulink, and the results are validated by the design and development of a hardware prototype.

Cryogenic Accelerated Fatigue Tester for additive manufactured polymer composite mechanical property measurement

Additive manufacturing (AM) of polymer matrix composite (PMC) materials maintains the potential to significantly reduce part count, weight, and costs for future aerospace development. However, a lack of maturity in loading systems has inhibited the characterization of these materials for the cryogenic environment of space. These PMCs demand lifespan endurance when faced with cryogenic thermal cycling in series with high-frequency mechanical loading. Few mechanical testers have been capable of achieving the cryogenic temperatures and actuating frequency to simulate the environment that a PMC endures in a cryogenic application. Also, these testers have yet to define the tensile and fatigue PMC mechanical behavior at these temperatures. To curate a cryogenic, fatigue profile on PMCs, the Cryogenic Accelerated Fatigue Tester (CRAFT) was developed. CRAFT utilizes a 12-kN load frame in unison with a cryocooler to perform tension-tension and tension-compression fatigue tests up to 100 Hz in a liquid hydrogen environment. This publication reviews the CRAFT design and capabilities. Determining the cryogenic fatigue life of 3D-printed PMCs through testing in CRAFT allows for the validation of proper material implementation and the future optimization of these materials in cryogenic environments.

Additive manufacturing of a compliant mechanism using Zr-based bulk metallic glass

• Additively manufactured moving structure with a compliant mechanism using bulk metallic glass. • Zr-based bulk metallic glasses demonstrate excellent resilience for compliant mechanisms. • The nominal rotational elastic motion can be increased by roughly 300% compared to Ti6Al4V in an exemplary compliant mechanism. Compliant mechanisms offer several advantages compared to rigid mechanisms, such as lower friction, backlash, and reduced part count which makes them attractive for structural and medical applications. However, their motion is limited by the elastic properties of the used material. Bulk metallic glasses offer a unique combination of high strength and large elastic deformation which suggests a high potential for the application in compliant mechanisms. This unique property profile originates from the amorphous structure, which results from the rapid cooling of tailored glass-forming alloy compositions. Recently, additive manufacturing via laser powder bed fusion established as a pivotal technology to overcome the limitations of size and complexity during the fabrication of bulk metallic glasses. This work presents the fabrication of a compliant mechanism via laser powder bed fusion that utilizes the unique elastic properties of the Zr 59.3 Cu 28.8 Al 10.4 Nb 1.5 bulk metallic glass forming alloy in combination with the geometrical freedom of additive manufacturing.

A Systematic Review of Compliant Mechanisms as Orthopedic Implants

Abstract Currently available motion-preserving orthopedic implants offer many advantages but have several limitations to their use, including short device lifetime, high part count, loss of natural kinematics, and wear-induced osteolysis and implant loosening. Compliant mechanisms have been used to address some of these problems as they offer several potential advantages - namely, wear reduction, reduced part count, and the ability to achieve complex, patient-specific motion profiles. This article provides a systematic review of compliant mechanisms as orthopedic implants. Based on the PRISMA guidelines for an efficient review, this work identified fourteen implantable orthopedic devices that seek to restore anatomical motion by utilizing mechanical compliance. From reviewing these implants and their results, advantages and consequences for each are summarized. Trends were also identified in how these devices are capable of mitigating common challenges found in orthopedic design. Design considerations for the development of future compliant orthopedic implants are proposed and discussed.

Improved 25-level inverter topology with reduced part count for PV grid-tie applications

<span lang="EN-US">A new bidirectional multilevel inverter topology with a high number of voltage levels with a very reduced number of power components is proposed in this paper. Only TEN power switches and four asymmetric DC voltage sources are used to generate 25 voltage levels in this new topology. The proposed multilevel converter is more suitable for e-mobility and photovoltaic applications where the overall energy source can be composed of a few units/associations of several basic source modules. Several benefits are provided by this new topology: Highly sinusoidal current and voltage waveforms, low Total Harmonic Distortion, very low switching losses, and minimum cost and size of the device. For optimum control of this 25-level voltage inverter, a special Modified Hybrid Modulation technique is performed. The proposed 25-level inverter is compared to various topologies published recently in terms of cost, the number of active power switches, clamped diodes, flying capacitors, DC floating capacitors, and the number of DC voltage sources. This comparison clearly shows that the proposed topology is cost-effective, compact, and very efficient. The effectiveness and the good performance of the proposed multilevel power converter (with and without PWM control) are verified and checked by computational simulations.</span>

A novel generalised topology of a reduced part count multilevel inverter with level boosting network to improve the quality of supply

Power quality is the measure problem to be under consideration when multilevel inverters (MLI) are employed. Multilevel inverters are used with integration of renewable energy sources. Problem of power quality arises when integrating renewable energy sources to the grid through MLI's. In this paper a generalised topology is proposed to reduce the part count by using the MLI with level boosting network (LBN). Photo voltaic cell can be used as an alternative source. MLI has n number of repeating units with a LBN which helps in generating 4n+3 output voltage levels. The proposed topology is carried out for 11 levels with two repeating units under LBN. The analysis is carried out considering different modes of operation and compared with the H-bridge circuit. Proposed MLI is supplied to the resistive and inductive (RL) load and it is also capable of feeding the local feeder. The simulation is done using MATLAB Simulink.

Photovoltaic - Battery Operated Electric Vehicle with an Energy Management Strategy

Hybrid energy storage systems have many advantages, including the use of multi-input converters, such as reduced part count, flexibility power, and absolute control of energy sources. In these systems, an Energy Management Strategy must wisely determine the power levels of the sources. Energy management strategy for photovoltaic/ battery including a bidirectional multiple - input converter electric vehicle is presented in this article. The proposed Energy management strategy not only regulates the state-of-charge of photovoltaic. The battery power profile is also smoothed by using a fuzzy controller and a rate limiter. Since the energy transfer between battery and Photovoltaic is free in this multi-input converter. This results in a hybrid energy storage system that is sustainable and has improved battery life. The feasibility of the proposed system is systematically tested by a simulation study and an observational framework involving an actual electric vehicle. In this paper the results proves that Energy Management Strategy for photovoltaic including electric vehicle is presented. The enhancement of the battery cycle-life is discussed because of the battery / PV hybridization based on experimental performance.

Compliant Mechanisms That Use Static Balancing to Achieve Dramatically Different States of Stiffness

Abstract Stiffness in compliant mechanisms can be dramatically altered and even eliminated entirely by using static balancing. This requires elastic energy to be inserted before operation, which is most often done with an additional device or preloading assembly. Adding such devices contrasts starkly with primary motivations for using compliant mechanisms, such as part count reduction, increased precision, and miniaturization. However, statically balanced compliant mechanisms with a fully monolithic architecture are scarce. In this article, we introduce two novel statically balanced compliant mechanisms with linear and rotary kinematics that do not require preloading assembly, enabling miniaturization. Static balance is achieved by the principle of opposing constant force and extended to a rotational device by using opposing constant torque mechanisms for the first time. A constant force mechanism based on existing work is used and inspired a novel constant torque mechanism. A single-piece device is obtained by monolithically integrating a bistable switch for preloading, which allows static balance to be turned on and off. The linear device reduces stiffness by 98.5% over 10 mm, has significantly reduced device complexity and has doubled relative range of motion from 3.3% to 6.6% compared to the state of the art. The rotary device reduces stiffness by 90.5% over 0.35 rad.

Additive Manufacturing in Industry

The advent of additive manufacturing (AM) processes applied to the fabrication of structural components has created the need for design methodologies and structural optimization approaches that take into account the specific characteristics of the fabrication process. While AM processes give unprecedented geometrical design freedom, which can result in significant reductions in the components’ weight (e.g., through part count reduction), on the other hand, they have implications for the fatigue and fracture strength, because of residual stresses and microstructural features. This is due to stress concentration effects, anisotropy, distortions and defects whose effects still need investigation. This Special Issue aims at gathering together research investigating the different features of AM processes with relevance for their structural behavior, particularly, but not exclusively, from the viewpoints of fatigue, fracture and crash behavior. Although the focus of this Special Issue is on AM, articles dealing with other manufacturing processes with related analogies can also be included, in order to establish differences and possible similarities.

Regression analysis of hardness property of laser additive manufactured (LAM) Ti and TiB2 metal matrix composite

Abstract Additive manufacturing has gained relevance in aerospace components for intricate lattice, cooling channels, complex internal structure, and lightweight strong structures. Additive manufacturing has aided cost saving by reducing part count in expensive materials. Titanium di boride is a hard ceramic with a good oxidation stability with resistance to mechanical wear. It is a hexagonal crystal structured with a non-lustrous grey appearance. It has expressed a high value of strength to density ratio, melting point, and wear resistance. A predictive correlation and relationship between the optimal parameters and the hardness was examined. The data analysis of their relationship was examined in statistical analysis. A predictive mathematical formula was derived, and a linear and quadratic polynomial regression machine learning details of the factors showed correlation.

Investigation on part consolidation for additive manufacturing with SIMP method

Additive manufacturing (AM) process comprises of different technologies which fabricate physical components from 3D CAD models by adding material layer-upon-layer. The unique capabilities of AM technologies are shape complexity, material complexity and hierarchical complexity. These enable new opportunities for customization of the product; fabricate intricate and complex shapes easier than the traditional method. Therefore, AM allows to consolidate the number of parts of an assembly to a single component and fabricate it. Though reducing part count in the assembly can avoid some assembly operations, the fullest potential of AM could not be achieved without material reduction. So the optimization step employed to lightweight the design. This paper demonstrates the above with an assembly of bactibiogramscope gantry head. Solid Isotropic Material with Penalization (SIMP) used to minimise material consumption. The optimised assembly was fabricated by the Fused Deposition Modelling (FDM) process. The final design was evaluated by comparing FEA result with experimental results. It also shows that topology optimized consolidate assembly take less time and material fabricate. This paper highlights the integration of part consolidation and topology optimizations to capitalize on the AM technique for fabricating better products.